Conventional internal combustion engines operate on all cylinders regardless of power requirements, relying upon transmission shifts and/or fuel supply to vary the torque provided in accordance with demand. During most normal driving cycles only a portion of available engine power is utilized, but the entire engine is used for that portion of power. The result is inherent inefficiency of operation, wasted energy, excessive fuel consumption and excessive pollutant emissions.
The present invention overcomes many of the disadvantages of the usual internal combustion engines. In accordance with one form of the present invention, a modular engine assembly is provided which incorporates a "floating" flywheel and a plurality of engines which selectively engage the flywheel via automatic clutches. Initially, the vehicle transmission is driven by a single, primary engine which also drives the flywheel. As additional power is required, as indicated by a torque sensor, or as demanded by an overriding foot pedal position, an auxiliary engine (one or more) is initially started by clutch coupling to the flywheel and thereafter aids the primary engine in driving the transmission.
Modular design enables the practical use of inexpensive, efficient, low polluting, small bore internal combustion engines (e.g. 10-90 cubic inches displacement). Synchronization of spark firing of the primary and auxiliary engines is readily accomplished by a commercially available mini-computer device. While the primary engine includes a starter and manual or automatic choke, the auxiliary engine is supplied, in one form hereof, with a fixed, idealized air/fuel ratio, such as stoichiometric or leaner. Heat transferred from the primary engine to the auxiliary engine maintains the auxiliary engine in a "ready" condition. A sealed housing is provided around the flywheel and vacuum therein is established by connection to the intake manifold of the primary engine. Additionally, the primary engine drives the alternator, air conditioner, and/or other pumps and the like, in the usual manner. Preferably, a hydrostatic transmission is utilized which provides smooth, full-range control of speed and torque. Fluid slip clutches, such as silicon fluid clutches, are preferred so as to provide full floating operation of the flywheel during braking and idling conditions.
The present modular-floating flywheel construction of one form of the present invention permits even the primary engine to stop, rather than be operating, during a temporary pause in vehicle travel, since the flywheel will act to start the primary engine as well as the auxiliary engine. The result is a further reduction in fuel consumption and air pollution.
The "floating" flywheel permits a smoothness of operation usually obtained only with rotary power engines, enables the storage of normally wasted energy and provides for rapid acceleration when required. The effective horsepower of the engine is thus efficiently increased. The primary and auxiliary engines can be identical or can be different, and engines as small as 20 horsepower can be used in conjunction with a larger (50-75 horsepower) engine to effectively drive a full sized automobile. Each engine is complete within itself, having the standard balancing flywheel, common to reciprocating piston engines. Pollutant emissions are low as a result of the extremely low fuel consumption and ability to drive the auxiliary engine with a fixed air/fuel ratio. Accordingly, the present invention provides an advantageous solution to current critical problems of fuel shortage and air pollution.
In another form of the present invention, primary and auxiliary engines of the rotary type are selectively coupled and decoupled one to the other depending upon power requirements during a particular driving condition. The mechanism for coupling and decoupling the engines includes a clutch having a heavy flange and which flange is continuously driven by the primary engine. The flange stores kinetic energy under normal conditions during which additional power beyond that afforded by the primary engine alone is not required. When such additional power is required, the clutch is actuated to couple the auxiliary engine to the rotating flange and the primary engine. The stored kinetic energy is utilized to bring the auxiliary engine up to or turn it over to a predetermined speed.
As the auxiliary engine is brought up to such speed by transfer of the stored kinetic energy from the flange to the auxiliary engine, a vacuum pressure actuated switch turns on the ignition for the auxiliary engine. Subsequently and at a higher vacuum pressure, an electrically actuated control valve shifts to communicate vacuum pressure from the manifold of the auxiliary engine to a vacuum slave valve. The latter vacuum, when subjected to such vacuum pressure, opens the throttle valve in the carburetor of the auxiliary engine. Thus, a fuel-air mixture is provided the auxiliary engine only after it is brought up to speed and its ignition is on. This substantially reduces emissions and provides for a lean burn.
In shutting down the auxiliary engine, the sequence is reversed. That is, the clutch is deenergized and the auxiliary engine is disconnected from the drive train. The control valve also shifts causing the slave valve to close the throttle valve and prevent further delivery of the fuel-air mixture to the auxiliary engine. As the auxiliary engine winds down, the vacuum switch turns off the ignition. By turning the ignition off after delivery of the fuel-air mixture is stopped, emission of unburned fuel is prevented. This vacuum operated system may also be utilized with primary and auxiliary engines of the piston as well as rotary types.